The grey-throated leaftosser (''Sclerurus albigularis'') is a

Near Threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

species of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

in the subfamily Sclerurinae, the leaftossers and miners, of the ovenbird

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Furnariidae. It is found in

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, and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

.Clements, J. F., T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2022. The eBird/Clements checklist of birds of the world: v2022. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ retrieved November 10, 2022

Taxonomy and systematics

The grey-throated leaftosser's taxonomy is unsettled. The

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(IOC) and the

Clements taxonomy ''The Clements Checklist of Birds of the World'' is a book by Jim Clements which presents a list of the bird species of the world. The most recent printed version is the sixth edition (2007), but has been updated yearly, the last version in 202 ...

assign it these seven subspecies: *''S. a. canigularis'' Ridgway, 1889 *''S. a. propinquus''

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, 1899 *''S. a. albigularis'' Sclater, PL & Salvin, 1869 *''S. a. kunanensis'' Aveledo & Ginés, 1950 *''S. a. zamorae'' Chapman, 1923 *''S. a. albicollis'' Carriker, 1935 *''S. a. kempffi'' Kratter, 1997

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's ''

Handbook of the Birds of the World The ''Handbook of the Birds of the World'' (HBW) is a multi-volume series produced by the Spanish publishing house Lynx Edicions in partnership with BirdLife International. It is the first handbook to cover every known living species of bird. ...

'' (HBW) does not recognize ''S. a. kunanensis''.HBW and BirdLife International (2022) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 7. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v7_Dec22.zip retrieved December 13, 2022 That subspecies might not be distinguishable from the

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''S. a. albigularis''.Remsen, Jr., J. V. (2020). Gray-throated Leaftosser (''Sclerurus albigularis''), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.grtlea1.01 retrieved April 29, 2023 The grey-throated and

rufous-breasted leaftosser The rufous-breasted leaftosser (''Sclerurus scansor'') is a species of bird in the subfamily Sclerurinae, the leaftossers and miners, of the ovenbird family Furnariidae. It is found in Argentina, Brazil, and Paraguay. Taxonomy and systematics ...

(''S. scansor'') are

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

.Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 30 January 2023. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved January 30, 2023 This article follows the seven-subspecies model.

Description

The grey-throated leaftosser is one of the larger members of genus ''Sclerurus''. It is long and weighs . The sexes are alike. The nominate subspecies has a grayish brown face with a somewhat scaly appearance. Its crown and back are rich chestnut-brown and its rump and uppertail

coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are small feathers behind t ...

are a brighter reddish chestnut. Its flight feathers are rich brown and its tail is dark gray-brown. Its throat is grayish white with a darker lower edge, its breast dark rufous with some pale streaks, its belly dark brown, and its flanks and undertail coverts a richer brown. Its iris is dark brown to brown, its

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

black to dark gray, its

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

pale grayish white to yellowish (sometimes with a dark tip), and its legs and feed black to brown. Juveniles resemble adults but are overall duller and have some dusky scaling on the throat. Subspecies ''S. a. propinquus'' has darker upperparts, breast, and belly than the nominate, and its throat is grayer. ''S. a. canigularis'' is generally darker than ''propinquus'' but its rufous cast is brighter than on both ''propinquus'' and the nominate. ''S. a. zamorae'' is generally darker than the nominate, with duller chestnut rump and uppertail coverts, a less whitish chin, and a brighter upper breast. ''S. a. albicollis'' has brighter and more

rufescent Rufous () is a color that may be described as reddish-brown or brownish-red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a dia ...

upperparts than the other subspecies; its uppertail coverts are especially rich rufous. It has paler underparts than most others and a white throat. ''S. a. kempffi'' is the palest subspecies, with a grayer breast and belly and less reddish upper breast and back than the others. Its rump is the same color as its back. Some authors state that ''S. a. kunanensis'' has a somewhat greenish olive belly, some olive on its flight feathers, and a blackish tail but others find no difference between it and the nominate.

Distribution and habitat

The grey-throated leaftosser has a

disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...

. The subspecies are found thus: *''S. a. canigularis'', Costa Rica and western Panama *''S. a. propinquus'', the

Sierra Nevada de Santa Marta The Sierra Nevada de Santa Marta (English: ''Snow-Covered Mountain Range of Saint Martha'') is an isolated mountain range in northern Colombia, separate from the Andes range that runs through the north of the country. Reaching an elevation of ...

of northern Colombia *''S. a. albigularis'', eastern Colombia, northern Venezuela, Trinidad, and Tobago *''S. a. kunanensis'', northern Venezuela's

Paria Peninsula The Paria Peninsula () is a large peninsula on the Caribbean Sea, in the state of Sucre in northern Venezuela. Geography Separating the Caribbean Sea from the Gulf of Paria, the peninsula is part of the mountain range, in the Venezuelan Coa ...

*''S. a. zamorae'', from

Napo Province Napo () is a province in Ecuador. Its capital is Tena. The province contains the Napo River. The province is low developed without much industrial presence. The thick rainforest is home to many natives that remain isolated by preference, descend ...

in eastern Ecuador south to Peru's

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*''S. a. albicollis'', disjunctly in southeastern Peru, the eastern Andean foothills in Bolivia, and several areas in southwestern Brazil *''S. a. kempffi'', the Serranía de Huanchaca in Bolivia's Santa Cruz Department The grey-throated leaftosser inhabits

evergreen forest An evergreen forest is a forest made up of evergreen trees. They occur across a wide range of climatic zones, and include trees such as conifers and holly in cold climates, eucalyptus, live oak, acacias, magnolia, and banksia in more temperate zo ...

, usually in foothills and lower montane areas, though in places it ranges both higher and lower. In the northeastern part of its range it approaches sea level and in Brazil it is strictly in the lowlands. In Costa Rica it occurs between of elevation, in Colombia between , and in Ecuador mostly between .

Behavior

Movement

The grey-throated leaftosser is a year-round resident throughout its range.

Feeding

The grey-throated leaftosser forages mostly on the ground, flipping aside leaves, probing the ground and gleaning from it and leaf litter while hopping rather than walking. It usually forages singly or in pairs; it does not join

mixed-species foraging flock A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock (birds), flock of usually insectivorous birds of different species that join each other and move together while fora ...

s. Its diet has not been detailed but has been documented to include beetles, spiders, cockroaches, and tiny frogs.

Breeding

The grey-throated leaftosser breeds between October and May in Trinidad and its season in Colombia includes at least May and June; its breeding seasons elsewhere have not been documented. The species is assumed to be monogamous. It nests in a burrow with a cup of leaves in a chamber at its end. The clutch size is two eggs.

Vocalization

The grey-throated leaftosser's song is "a series of 4–6 tripled rising notes, 'kwu-kwu-kwe-kwe-kwi-kwi' " that sometimes has "musical trills" within it and at the end. Another description of it is "squeaky, plaintive, ascending, whistled notes, 'tuéé, tuéé, tuéé, tweééptu'." Its alarm call is "a squeaky, sharp 'cheek' or 'chik-chik'."

Status

The

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

originally assessed the grey-throated leaftosser as being of Least Concern but since 2012 has rated it Near Threatened. It has a fairly large but disjunct range and an unknown population size; the latter is believed to be stable. It is "particularly susceptible" to forest fragmentation and disturbance so deforestation is the principal threat. It is overall considered rare to locally uncommon, though locally fairly common in Venezuela. It does occur in several protected areas.

References

{{Taxonbar, from=Q844032 grey-throated leaftosser Birds of Costa Rica Birds of the Northern Andes Birds of Trinidad and Tobago grey-throated leaftosser grey-throated leaftosser grey-throated leaftosser Taxonomy articles created by Polbot